Gaseous electric discharge lamp device



Dec. 21, 1937. I I A. RUTTENAUER 2,

GASEOUS ELECTRIC DISCHARGE LAMP DEVICE Original Filed Dec. 2, 1936 INVENTOR Alfred Rufitenauer Patented Dec. 21, 1937' Alfred Rnttenauer, Berlin-Halensec, assignor to General Electric Company, a corporation of New York Application December 2, 1936, Serial No. 113,897. Renewed August 24, 1937. In Germany Maytric discharge lamp devices having a gaseous iilling comprising'mercury vapor and a coating of luminescent material on the inner surface of,

the lamp container.

It is frequently desirable to modify the appearance of the mercury vapor discharge in mercury, vapor 1 amps and luminescent material,

such as zinc silicate which emits a yellow light,

is useful for this purpose. It is possible to modithat the tube has a white appearance.

ever, the mixed Howlight of the mercury vapor discharge and the yellow luminescent material does not contain all the colors found in daylight and for this reason this type of lamp device is more useful for outdoor advertising purposes than for purposes of interior illumination.

- The object of vide a mercury the present invention is to provaporv discharge lamp having a coating of luminescent material on the inner surface thereof to daylight. tages attaching which lamp emits light similar Still further objects and advanto the device and to its use and operation will be apparent to those skilled in the artfrom the following particular description.

I have discovered that a mercury vapor discharge lamp having a coating of cadmium silicate on the inner surface of-the lamp containeremits light similar to daylight when the current density of the discharge is approximately 0.1-0.5 amp/cm and when the cadmium silicate contains .5 to 0.1% manganese. These limits of current density and manganese conganesecontent When the manof the cadmium silicate is greater than 1% or less than 0.5% the light output of the material is not-suflicient to balance the light output of the mercury vapor discharge so that the light emitted by the mercury vapor discharge preponderates in the light emitted by the lamp. When the current density of the discharge is greater than 0.5 amp/cm? the mercury va por light preponderates in the light emitted by the lamp and when the current density of the discharge is less than 0.1 amp/cm the light emitted by the cadmium silicate preponderates in the light emitted by the lamp.

The light emi tted by the cadmium silicate l8 10 Claims. (01. 176-122) The present invention relates to gaseous elecorange, and thus has much more red in it than has daylight. This is desirable, however, since the luminescent light constitutes but a part of the total light output of the lamp and-the excess of red in the luminescent light serves to balance the light from the mercury vapor discharge which contains no red rays.

The light emitted by a lamp having the structure described above contains all the colors contained in daylight, that is the violet, blue, green and yellow rays of the mercury vapor discharge and the yellow-red rays of the light emitted by the fluorescent material. While there is a slight color gap between the blue and the green mercury lines this is not of practical importance.

when light very closely approximating daylight is desired, for example in illuminating dyeing establishments, a luminescent material emitting a blue-green light is added to the cadmium silicate, which cadmium silicate is activated by 0.5 to 1% manganese. Preferably this luminescent material constitutes 10 to 30% of the cadmium silicate'and is mixed therewith and applied to the inner surface of the lamp container. Zinc tungstate or magnesium tungstate is preferred for this purpose.

In the drawing accompanying and forming part of this specification an embodiment of the invention is shown in a side elcvational, partly sectional view. j

Referring to the drawing the gaseous electric dischargelamp device comprises an elongated tubular container I having electrodes 2 and 3 sealed therein at the ends thereof. The electrodes 2 and Iare electron emitting and consist of a pellet of electron emitting material, such as barium oxide, and afllament of, high melting point materiaL'such as tungsten, wrapped around said pellet. Said container I has a gaseous atmosphere therein consisting of 40 a starting gas, such as argon, and a quantity I of vaporizable material, such as mercury, the vapor of which emits light during the operation of the device. A lamp having this structure is capable of operation with a discharge 4,5 current density of between 0.1-0.5 amp/cm.

Said container I has a coating] of powdered luminescent material on the inner surface thereof (indicated by dotted lines in the drawing).

The luminescent coating 4 consists of the material or materials disclosed above. 4 The particles of luminescent material are applied to the inner surface of said container l by methods now known in the art, such as by first covering the inner surface of said container I with a volatlliaable bindto whenvheated 1 er, such as a mixture of glycerin and alcohol, and then applying the luminescent particles, as by dusting, to the binding material. The binder is then volatilized and removed from the container I, as by heating and exhausting said container I. A firmly adherent luminescent coating is thus applied to the inner surface of the container I.

A lamp having the structure described above is an efficient light source useful for illuminating purposes and the color of the light emitted thereby is similar to daylight.

It will be understood, of course, that I contem-' plate that numerous changes in the form and details of the device illustrated may be made by those skilled in the art without departing from the spirit and scope of the invention, for example; the luminescent coating 4 may completely cover the inner surface of the container I, or may be applied to selected .portions of said surface, when desired.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. A gaseous electric discharge lamp device comprising a container, electrodes sealed therein, a gaseous atmosphere therein comprising mercury vapor and a coating of cadmium silicate associated with said lamp, said cadmium. silicate containing from 0.5 to 1% manganese;

2. A gaseous electric discharge lamp device.

comprising a container, electrodes sealed therein, a gaseous atmosphere .therein comprising mercury vapor and a coating of luminescent material associated with said lamp, said coating consisting of from 10 to 30% of fluorescent materialemitting green light and from to of cadmium silicate, said cadmium silicate containing from 0.5 to 1% manganese.

3. A gaseous electric discharge lamp device comprising a container, electrodes sealed therein, a gaseous atmosphere therein comprising mercury vapor and a coating of luminescent material associated with said lamp, said coating consisting of from 10 to 30% of zinc tungstate and from '70 to 90% of cadmium silicate, said cadmium silicate containing from 0.5 to 1% manganese. v

4. A gaseous electric discharge lamp device comprising a container, electrodes sealed therein, a gaseous atmosphere therein comprising mercury vapor and a coating of luminescent material associated with said lamp, said coating consisting of from 10 to 30% of magnesium tungstate and from 70 to 90% of cadmium silicate, said cadmium silicate containing from 0.5 to 1% manganese.

5. A gaseous electric discharge lamp device of cadmium silicate, said cadmium comprising a container, electrodes sealed therein, a gaseous atmosphere therein comprising mercury vapor and a coating of cadmium silicate on the inner wall of said lamp and exposed to the discharge therein, said cadmium silicate containing from 0.5 to 1% manganese.

6. A gaseous electric discharge lamp device comprising a container, thermionic electrodes sealed therein, a gaseous atmosphere therein comprising mercury vapor and a coating of cadmium silicate on the inner wall of said lamp and exposed to the discharge therein, said cadmium silicate containing from 0.5 to 1% manganese.

7. A gaseous electric discharge lamp device comprising a container, thermionic electrodes sealed therein and supporting a discharge therein having a current density of the order of 0.1-0.5 amp/cm a gaseous atmosphere therein comprising mercury vapor and a coating of cadmium silicate on the inner wall of said lamp and exposed to the discharge therein, said cadmium silicate containing from 0.5 to 1% manganese.

8. A gaseous electric discharge lamp device comprising a. container, electrodes sealed therein, a gaseous atmosphere therein comprising mercury vapor and a coating of luminescent material on the inner wall of said lamp and exposed to the discharge therein, said coating consisting of from 10 to 30% of fluorescent material emitting green light and from '70 to 90% of cadmium silicate, said cadmium silicate containing from 0.5 to 1% manganese.

9. A gaseous electric discharge lamp device comprising a container, thermionic electrodes sealed therein, a gaseous atmosphere therein comprising mercury vapor and a coating of luminescent material on the inner wall of said lamp and exposed to the discharge therein, sa d coating consisting of from 10 to 30% of fluorescent material emitting green light and from '70 to 90% silicate containing from 0.5 to 1% manganese.

10. A gaseous electric discharge lamp device comprising a container, thermionic electrodes sealed therein and supportinga discharge therein posed to the discharge therein, said coating consisting of from 10 to 30% of fluorescent material 7 emitting green light and from 70 to 90% of cadmium silicate, said cadmium silicate containing from 0.5 to 1% manganese.

ALFRED RUTIENAUER. 

